In the present invention, a user may place an original document onto the platen of a digital copier where the placement is at a large angle to the platen, which would normally be noticed and corrected by this user before copying the document. In contrast, the placement could be at a slight angle to the platen, which is unnoticed, or the user could be in a rush and non-observant, and this can result in a skewed image of the original document being saved in the copier memory for printing. Further, the cover of a digital copier can become dirty forming a non-white area around the image of the original document, reducing the quality of the printed document. To overcome these problems, a user will desire to blank out all of the unwanted platen and cover artifacts that would surround the image of the skewed original document without causing any of the original document's data to be lost.
Traditionally, the blanked region is orthogonal to the scanner array on all four sides of the full image area. The drawback for the traditional approach is that by using known orthogonal blanking techniques to remove the artifacts in severely skewed originals, part of the original's content may be removed and the artifacts, e.g., platen show through and copier top dirt, may not be completely eliminated. As can be clearly seen in prior art FIG. 1, the original document was scanned into the digital copier at a severely skewed angle. Using a conventional blanking technique, the original document 2 is blanked orthogonally, as is shown as 6, which clearly cutoff parts of the original document 4 and its data, and left artifacts 8, e.g., platen show through and copier top dirt, reducing the quality of the image and resulting print. The conventional way of blanking around a document is by raster scanning around a margin of the document which replaces pixels with a predetermined pixel value using a set size of the margin. Unfortunately, this usually results in the cutting off of parts of the original document containing important data and leaving of the background artifacts.
It would be advantageous if the background of the image of the original document could be completely blanked, regardless of that fact that the document was placed on the platen at a small or severely skewed angle, without any loss of data. It also would be advantageous if the blanking technique ensured that a user could completely blank the regions surrounding the document so that no data of the document was lost and all of the background artifacts, caused by the platen show through and a dirty top of a digital copier, were removed thus leaving a more accurate and more perfect image of the original document to be printed than conventional blanking techniques.
Unfortunately, known systems do not provide for blanking out regions surrounding the document where they only blank out horizontal and vertical regions on the edges of the image. In doing this, the blanking will remove desired data from the image from the original document, and will leave behind background artifacts of platen show through and copier top dirt which reduces the quality of the image to be printed.
The present invention contemplates a new skew blanking technique which achieves the above-referenced advantages, and others, and resolves appurtenant difficulties.